Unfold the pastry sheet on a lightly floured surface. Roll the pastry sheet into a 16x12-inch rectangle. With the short side facing you, spoon the chicken mixture onto the bottom half of the pastry sheet to within 1-inch of the edges. Starting at the short side, roll up like a jellyroll. Place the pastry roll seam-side down on a baking sheet. Tuck the ends under to seal. Brush with the egg mixture and sprinkle with the parsley. Cut 2-inch slits 2 inches apart on the top.

Bake for 30 minutes or until the pastry is golden. Slice and serve warm on the salad greens with the sour cream, if desired.